Magnetic annunciator

Abstract

An annunciator is provided for an organ stimulating system which is implantable in the body of a patient. A tubular support member is mounted at one end on the casing for the organ stimulating system and extends to a free end and an electrically conductive coil encircles the support member. An elongated oscillating member includes a field return member of magnetically permeable material which is spaced from and generally encircles the support member. The field return member extends between an integral head member at a proximal end generally proximate the free end of the support member and a distal end generally proximate the casing. A stack member is mounted on the head member and extends away therefrom toward the casing for the organ stimulating system. The stack member has an outer peripheral surface which is spaced from the support member and includes a magnetically permeable pole piece and a permanent magnet member, the pole piece and the magnet member being in stacked relationship which together produce a radial magnetic field which extends through the coil and to the field return member. A resilient member intermediate the stack member and the casing of the organ stimulating system biases the oscillating member to an initial position. With this construction, cyclic energization of the coil interacts with the radial magnetic field to cause the oscillating member to oscillate relative to the initial position. A similarly constructed activity sensor is also disclosed for relating patient movement.